Portable, battery-operated, electronic devices such as cell phones, media players, and location tracking devices are ubiquitous in today's world. To power or recharge these devices in a vehicle, power adaptors that connect a vehicle's electrical system directly to a portable device can be used. When the vehicle is operating or active, the electrical load on the vehicle from the power adapter and electronic device is small compared to the overall electrical demands from the vehicle itself. When the vehicle is not operating or inactive, however, and the power adapter and electronic device are left on, there will be a continual and significant drain on the vehicle's battery. To prevent depletion of a vehicle's battery, power adaptors have been designed to sense when a vehicle's ignition is turned to the off position, and then either turn off the device or drastically reduce its power consumption.